The present invention relates to a heteropolysaccharide (HP) characterized in that it can be obtained by fermentation of a medium including at least one Agrobacterium radiobacter I-2001 (or DSM 12095) strain, a recombinant thereof or mutant thereof, and a source of carbon which can be assimilated by said strain, a recombinant thereof or a mutant thereof.
In many industrial domains, there is a constant search for novel compounds with:
improved rheological properties, and which are capable of forming gels,
increased compatibility with the media into which they are incorporated,
great stability over a wide temperature and pH range.
In the case of compounds obtained at the end of a bacterial fermentation, it is also important for the compound to have good productivity.
The ability to gel is very advantageous since they are systems which are particularly attractive by virtue of the diversity of the domains in which they have applications: some applications require the use of a gel.
Thus, for example, the agrofoods industry provides a wide range of gelled products (creams, yoghurts, diverse jellies, ice creams, etc.), and the pharmaceutical industry uses gels as active principle or thickening agent supports.
In entirely another domain, some paints do not drip since they have gel characteristics when standing, whereas they spread easily with a paintbrush (rheofluidifying profile).
Aqueous gels are also used as chromatographic supports or for developing contact lenses.
Heteropolysaccharides of bacterial origin, such as for example xanthan gum, have already been described and used for their effective rheological properties under extreme temperature and pH conditions. However, these heteropolysaccharides, which are suitable in applications in solution, do not always produce gels.
It is known that the gelling of a medium takes place when a three-dimensional network is formed subsequent to the crosslinking of the components of said medium.
Conventionally, this gelling is brought about by adding additional cations in particular of alkali metal or alkaline earth metal type (for example calcium and/or magnesium) to the medium, by switching the pH toward acid or basic pHs, by adding another compound, in particular another polysaccharide (for example the combination of xanthan and carob), or by modifying the temperature.
Whatever the application envisaged, the abovementioned gelling conditions may:
harm the stability and the compatibility of the final gel due to the interactions between the additional cations or the coadditive, which must be introduced in order to obtain the gel, and the other ingredients present in said compositions, or
denature the heteropolysaccharide and/or the other ingredients present in said compositions due to the high temperatures and/or the pH changes.
In the context of the present invention, the term xe2x80x9cgelxe2x80x9d refers to a pseudosolid (behavior close to a solid) resulting from the association, at least partial, of heteropolysaccharide chains dispersed in a liquid. In a stressing frequency range xcfx89, the pseudo-solid gels are in general characterized, with regard to their solid component, by an elastic modulus Gxe2x80x2 (xcfx89) also called storage modulus and, with regard to their liquid or viscous component, by a viscous modulus Gxe2x80x3 (xcfx89) also called loss modulus.
The mechanical values Gxe2x80x2 (xcfx89) and Gxe2x80x3 (xcfx89) can be measured using a controlled strain rheometer and operating in oscillatory mode. By way of nonlimiting indication, mention may be made, for example, of a Rheo-Fluid Spectrometer(copyright) rheometer.
Gxe2x80x2 and Gxe2x80x3 can also be measured on a controlled stress rheometer and operating in oscillatory mode. By way of indication, mention may be made, for example, of a CARRIMED(copyright) rheometer.
The principle of the measurement consists in determining, firstly, the range of reversible mechanical strain in which the response of the gel to the mechanical stressing is linear as a function of said strain. Secondly, the gel is subjected to a set value of mechanical strain included in the linear range determined above. The rheometer then carries out a frequency sweep xcfx89.
The stress response of the gel which is in phase with the strain gives the elastic modulus Gxe2x80x2 (xcfx89). Gxe2x80x2 (xcfx89) corresponds to the energy stored by the gel in elastic form and can be recovered.
The stress response of the gel which is out of phase by an angle of 90xc2x0 with the strain gives the viscous modulus Gxe2x80x3 (xcfx89). Gxe2x80x3 (xcfx89) corresponds to the energy dissipated by the viscous flow and can not be recovered.
A gel is termed strong or true when, throughout the stressing frequency range (xcfx89) swept, the Gxe2x80x2/Gxe2x80x3 ratio is greater than or equal to 10, i.e. when the elasticity of the gel remains high and when the value of Gxe2x80x2 (xcfx89) is greater than or equal to 10 Pa.
The aim of the present invention is precisely to provide heteropolysaccharides which have very good rheological properties, in particular in terms of thickening and pseudoplastic (rheofluidifying) properties, and also the ability to produce true gels without adding additional cations to the medium and without switching the pH, this being at temperatures lower than or equal to 40xc2x0 C.
The aim of the present invention is also to provide a heteropolysaccharide with very good rheological properties at low concentrations.
The present invention therefore relates to a heteropolysaccharide (HP) characterized in that it can be obtained by fermentation of a medium including at least one Agrobacterium radiobacter I-2001 (or DSM 12095) strain, a recombinant thereof or a mutant thereof, and a source of carbon which can be assimilated by said strain, a recombinant thereof or a mutant thereof.
The Agrobacterium radiobacter strain was deposited in accordance with the Treaty of Budapest, with the Collection Nationale de Culture des Micro-organismes (CNCM) [National Collection of Microorganism Cultures], on Apr. 3, 1998, where it can be accessed publicly under the number I-2001. It was also deposited with the Deutsche Sammlung von Mikro-organismen und Zellculturen GmbH (DSMZ), on Apr. 21, 1998, where it can be accessed publicly under the number DSM 12095.
Pure culturing of Agrobacterium radiobacter I-2001 (or DSM 12095) can be carried out in Petri dishes incubated at a temperature of between 25xc2x0 C. and 30xc2x0 C., and more particularly of between 25xc2x0 C. and 28xc2x0 C., for approximately 24 hours.
The sources of carbon and nitrogen which can be assimilated by Agrobacterium radiobacter I-2001 (or DSM 12095) can be chosen from glucose, fructose, galactose, trehalose, mannose, melobiose, sucrose, raffinose, maltotriose, maltose, lactose, lactulose, methyl-xcex2-galactopyranoside, methyl-xcex1-galactopyranoside, cellobiose, gentobiose, methyl-xcex2-D-glucopyranoside, methyl-xcex1-D-glucopyranoside, esculin, ribose, arabinose, xylose, palatinose, rhamnose, fucose, melezitose, D(+) arabitol, L(xe2x88x92) arabitol, xylitol, dulcitol, tagatose, glycerol, myo-innositol, mannitol, maltitol, turanose, sorbitol, adonitol, lyxose, erythritol, D(xe2x88x92) tartrate, D(+) malate, L(xe2x88x92) malate, cis-aconitate, trans-aconitate, 2-keto-D-gluconate, N-acetylglucosamine, guinate, betaine, succinate, fumarate, glycerate and glucosamine.
Among the possible maintenance media for the strain, the maintenance medium of the type Difco MY agar (reference 0712-01-8) is considered to be particularly advantageous. Said Difco MY agar medium has the following composition:
For conserving the strain, it is preferable to anticipate at least one preculturing step. The term xe2x80x9cpreculturing stepxe2x80x9d is intended to mean a step which consists in developing and multiplying the bacterial strain, without polysaccharide production.
It has been possible to demonstrate that, in general, the heteropolysaccharide (HP) includes glucose motifs and/or derivatives thereof, galactose motifs and/or derivatives thereof, glucuronic acid motifs and/or salts thereof, acetic acid motifs and/or salts thereof, and pyruvic acid motifs and/or salts thereof.
The constituent motifs of the heteropolysaccharide (HP) are in general present in molar proportions as follows, taking, as a reference, glucose to be equal to 1:
galactose and/or derivatives thereof 0.2-5,
glucuronic acid and/or salts thereof 0.1-3,
acetic acid and/or salts thereof 0-5,
pyruvic acid and/or salts thereof 0.01-2.
More particularly, said motifs are present in molar proportions as follows, taking, as a reference, glucose to be equal to 1:
galactose and/or derivatives thereof 0.5-4, and preferably 0.8-2,
glucuronic acid and/or salts thereof 0.2-2, and preferably 0.4-1,
acetic acid and/or salts thereof 0-4, and preferably 0-3,
pyruvic acid and/or salts thereof 0.01-2.
The glucuronic, acetic and pyruvic acids can be in the form of salts. By way of salts, mention may be made of sodium, potassium, calcium or ammonium salts.
The principle of the methods of analysis of the heteropolysaccharide (HP) which have made it possible to determine its crude formula as specified above is the determination of the constituent elements (monosaccharides and acids) after hydrolysis of said heteropolysaccharide (HP) and chromatographic assays with internal or external calibration.
Thus, the monosaccharide assay was carried out in the following way: 100 mg of heteropolysaccharide (HP) are hydrolyzed in hermetic tubes with 5 ml of molar trifluoroacetic acid at 105xc2x0 C. for three to six hours.
This operation is followed by evaporation to dryness and taking up the dry residue in 5 ml of pyridine containing 15 mg of sorbitol as an internal standard; then silylation on 1 ml of pyridine solution, with 0.9 ml of hexamethyldisilazane. The silylation is catalyzed with 0.1 ml of trifluoroacetic acid.
The monosaccharide assay is then carried out by FID (Flame Ionization Detection) gas phase chromatography, on a glass capillary column 25 meters long and 0.25 mm in diameter, loaded with methylsilicone phase having a film thickness of 0.14 microns. The gas vector used is hydrogen, with a flow rate of 2 ml/minute.
The pyruvic acid assay is carried out using a stock solution obtained by hydrolyzing 50 mg of heteropolysaccharide (HP) using 5 ml of 1N hydrochloric acid for 1 hour at 105xc2x0 C., then adding 2 mg of ketoglutaric acid (constituting the internal standard) and adjusting to 25 ml with distilled water. This operation is followed by reaction with 2,4-dinitrophenylhydrazine (DNPH):
1 ml of solution of DNPH at 7 mg/ml in 2N HCl is added to 1 ml of the above solution;
the reaction time is 5 minutes; then
2 ml of acetone and 6 ml of water-acetonitrile mixture are added.
The assay is then carried out by High Performance Liquid Chromatography (HPLC) using a column loaded with 5 micron diameter C-18 grafted silica, the length of which is 250 mm and the diameter of which is 4.6 mm. The eluant used is a 50/50 mixture by volume of 0.02 mol/l phosphoric acid and of acetonitrile. The flow rate is 2 ml/minute.
The detection of the pyruvic acid is carried out using ultraviolet light at 375 nm.
The acetic acid assay takes place after hydrolysis of 100 mg of heteropolysaccharide (HP) with 5 ml of 2N hydrochloric acid at 105xc2x0 C. for one hour. 5 ml of a solution of propionic acid at 5 mg/ml are then added as an internal standard, and 15 ml of demineralized water are added to the mixture. The assay is carried out by HPLC using a 5 micron C-18 grafted silica column, 250 cm in length and 4.6 mm in diameter. The eluant is a 0.02 mol/l aqueous phosphoric acid solution at a flow rate of 1.2 ml/minute. The detection is refractometric.
The glucuronic acid is assayed via the CO2 released by the decarboxylation subsequent to the treatment, while hot, of the gum with hydrochloric acid according to the method described in the Food Chemical Codex, 4th edition, page 768.
The molar mass by weight is determined by exclusion chromatography on TSK PW 4000 and 6000 columns in series (columns 30 cm in length and 7 mm in diameter), with refractometric detection. The eluant is a 0.1 mol/l sodium nitrate solution. The heteropolysaccharide is at approximately 0.015% by weight in the eluant. The calibration is carried out using pullulanes, which are monodispersed polysaccharides of molar masses of between 5xc3x97103 and 1.6xc3x97106 g/mol extrapolated up to 107 g/mol.
The mean molar mass by weight (Mw) is obtained from the mass distribution curve derived from the chromatogram; it is generally between 1xc3x97105 and 5xc3x97106 g/mol, preferably between approximately 8xc3x97105 and 5xc3x97106 g/mol. The mean molar mass by weight is more particularly approximately 3xc3x97106 g/mol.
As already mentioned, the (HP) has very good rheological properties in solution, in particular in distilled water or mains water.
Thus, it could be noted that, for example, 1% weight/weight solutions of (HP) in distilled water at 23xc2x0 C., and at a frequency of 1 Hz, produce Gxe2x80x2 values of between 0.1 and 200 Pa and Gxe2x80x3 values of between 0.1 and 20 Pa.
(HP) produces strong or true gels when the Gxe2x80x2 and Gxe2x80x3 values are advantageously between 20 and 200 Pa for Gxe2x80x2 and between 0.5 and 15 Pa for Gxe2x80x3. Even more advantageously, Gxe2x80x2 is between 20 and 150 Pa and Gxe2x80x3 between 0.5 and 10 Pa. According to a particularly preferred embodiment, the Gxe2x80x2 value is approximately 100 Pa and that of Gxe2x80x3 is approximately 5 Pa (in distilled water).
The (HP) confers viscosity on the aqueous medium, which is evaluated by flow rheology. The rheological measurements of flow viscosity are carried out using a controlled stress rheometer or controlled shear rate rheometer, such as for example using a viscosimeter of RHEOMAT(copyright) or CARRIMED(copyright) type, respectively.
In both cases, the apparatus measures the stress upon flowing of the HP+water mixture when this mixture is irreversibly strained. The flow viscosity is calculated from the stress.
This apparatus thus makes it possible to quantify the viscosity level at a given shear rate.
The flow viscosity can be more simply evaluated using a BROOKFIELD(copyright) viscosimeter.
These rheological measurements of (HP) flow viscosity make it possible, in addition, to evaluate the flow threshold of the (HP) solution and/or of the formulation comprising it. Said threshold represents the strength which must be provided in order to destroy the structure of the medium and to force it to flow.
The flow rheology also makes it possible to quantify the ease with which an (HP) solution and/or a formulation comprising it flows when the controlled shear increases (pseudoplastic or rheofluidifying behavior).
It was noted, for example, that 1% weight/weight solutions of HP in distilled water containing 1% weight/weight of NaCl, at 23xc2x0 C., produces flow viscosity values, at a shear rate of 0.1 sxe2x88x921, of between 100 and 5000 Paxc2x7s, and more particularly of between 200 and 2000 Paxc2x7s.
Under similar conditions, at a shear rate of 10 sxe2x88x921 flow viscosity values of between 0.5 and 300 Paxc2x7s, and more particularly between 5 and 150 Paxc2x7s are produced.
These flow rheology data are representative of the behavior of the formulation when it is masticated, when it is poured, when it is overrun, etc.
The gels obtained by incorporating (HP) into the medium are cicatrizing gels, i.e. after shearing, even strong shearing, the xe2x80x9cfracturedxe2x80x9d gels have the power of reforming and of recovering their initial properties.
The cicatrizing power of the gels obtained from (HP) is evaluated using compression testing measurements carried out, for example, on an ETIA T2 texturizer composed of a cylindrical measuring body 12.7 mm in diameter, with a penetration rate of 0.05 mm/s and a penetration height of 15 mm. The plunger is pushed into the gel at the same place several times, at different time intervals, and the compression strength is recorded. The slope at the origin expressed in mN/mm, representative of the elasticity of the gel, is determined.
For example, a gel is prepared with 1% weight/weight of (HP) in distilled water. This gel is then stored for 24 hours before carrying out the compression testing measurements, either at room temperature (approximately 25xc2x0 C.) or in the cold at approximately 6xc2x0 C.
Compression testing measurements are carried out at different time intervals: 0, 5, 15 minutes and 24 hours, with a 5 minute gap between each measurement.
Thus, the slope remains constant is approximately equal to 45xc2x11 mN/mm, whatever the measurement time (t=0, 5, 15 minutes and 24 hours).
This means that the elasticity of the gel is stable and that it has the power to cicatrize several times in succession over time, while at the same time maintaining the same gel strength.
The present invention also relates to a process for preparing the heteropolysaccharide (HP) as defined above.
The preparation process consists, firstly, of the fermentation of a medium including at least one source of carbon which can be assimilated by an Agrobacterium radiobacter I-2001 (or DSM 12095) strain, a recombinant thereof or a mutant thereof.
Besides said source of carbon which can be assimilated, the fermentation medium can also contain at least one organic or inorganic source of nitrogen, and optionally one or more inorganic salts.
The medium is inoculated conventionally with the Agrobacterium radiobacter I-2001 (or DSM 12095) strain.
By way of an organic source of carbon which is a constituent of the fermentation medium, besides the sugars mentioned above, mention may also be made of sugars such as starch, advantageously hydrolyzed, starch hydrolysates, the mixtures of these sugars and the mixtures comprising at least one of these sugars.
More particularly, mention may be made of glucose, sucrose, starch, advantageously hydrolyzed, starch hydrolysates, lactose, the mixtures of these sugars and the mixtures comprising at least one of these sugars. Glucose and sucrose are the sugars which are even more preferred.
The carbon source concentration in the fermentation medium can be between 1 and 100 g/l, and preferably between 15 and 60 g/l.
By way of organic source of nitrogen, mention may be made of casein and caseinates, fish hydrolysates, wheat, corn or soya flours, yeast extracts (bakers"" yeast, brewers"" yeast, lactic yeasts, etc.), corn steap liquor (CSL), urea and potato proteins.
By way of inorganic sources of nitrogen, mention may be made of ammonium or sodium nitrates, and ammonium phosphates or sulfates.
The fermentation can also take place with a mixture of organic and inorganic sources of nitrogen.
The nitrogen-containing source (organic, inorganic or a mixture of the two) concentration in the fermentation medium can be between 1 and 80 g/l, preferably between 3 and 50 g/l.
The fermentation medium can also contain trace elements, such as traces of iron and/or of calcium and/or of manganese and/or of magnesium salts, and also vitamins and nucleotides.
The fermentation can be carried out at pressures of between 1 and 4 bar, at a temperature of between 25xc2x0 C. and 35xc2x0 C., preferably of between 25xc2x0 C. and 30xc2x0 C., under aerobic conditions.
The pH of the fermentation medium can be between 5 and 9, and preferably between 6 and 8. The pH can be adjusted, depending on the case, with a base such as sodium hydroxide, potassium hydroxide or aqueous ammonia, or with an acid such as sulfuric acid, phosphoric acid, hydrochloric acid or nitric acid.
The fermentation medium, placed in a fermentation tank or container, can be advantageously subjected to agitation. This agitation can be carried out, for example, using a reciprocal shaker, a rotary shaker, a stirring spindle or a column of bubbles. The fermentation time is conventionally longer than 30 hours, but generally between 40 and 100 hours.
The fermentation yields are generally greater than 40%, more particularly between 55 and 75% and most particularly between 60 and 75% by weight of heteropolysaccharide (HP) produced with respect to the source of carbon used.
After fermentation, the heteropolysaccharide (HP) can be separated from the fermentation must according to the following steps:
ixe2x80x94the end-of-fermentation must is subjected to heat treatment between 80xc2x0 C. and 120xc2x0 C. for 10 to 60 minutes,
iixe2x80x94the heteropolysaccharide (HP) is precipitated using an at least partially water-miscible organic liquid,
iiixe2x80x94the heteropolysaccharide (HP) is separated from the organic liquid.
In step (i), the fermentation must containing the heteropolysaccharide (HP) is advantageously heated at temperatures of between 80xc2x0 C. and 120xc2x0 C. for 10 to 60 minutes, and preferably for between 15 and 45 minutes.
The must subjected to the heat treatment above advantageously has a pH of between 6 and 8.
However, this pH can be adjusted if necessary, depending on the case, with a base or acid.
The latter can be chosen from the bases and acids mentioned above, used for adjusting the pH of the fermentation medium.
According to a preferred variant of the invention, the must derived from step (i) is maintained at the same temperature as the temperature of the heat treatment.
In step (ii), the heteropolysaccharide (HP) is recovered from the must obtained in step (i), advantageously by precipitation using an organic liquid which is at least partially water-miscible and in which the heteropolysaccharide (HP) is insoluble or practically insoluble.
By way of liquids which are suitable according to the present invention, mention may be made of acetone or alcohols which include 1 to 6 carbon atoms, such as ethanol, propanol, isopropanol, butanol, tert-butanol, or the mixture thereof.
More particularly, the precipitation of (HP) is carried out with isopropanol.
The volume of organic liquid used is generally at least twice that of the volume of must to be treated.
The precipitation of the heteropolysaccharide (HP) with an organic liquid can also be carried out in the presence of salts, such as sodium, potassium or calcium sulfates, chlorides or phosphates.
According to a particular embodiment, the precipitation can take place at a temperature of between 40 and 60xc2x0 C.
The heteropolysaccharide (HP), once precipitated, can then be separated, in step (iii), from the organic liquid.
The separation method is not critical in itself, and can be chosen equally from the usual known separation methods, such as for example filtration, centrifugation or spin-filtering.
The fibers obtained can be optionally dehydrated, for example using acetone or an alcohol such as ethanol, propanol or isopropanol.
The weight of alcohol required to carry out this dehydration operation is generally 1 to 10 times that of the fibers to be treated.
The dehydrated fibers can undergo further filtration, centrifugation or spin-filtering operations.
Where appropriate, the fibers can be dried, ground and/or sieved so as to obtain a heteropolysaccharide (HP) powder.
If the intention is to obtain a purer powder, it is possible to treat either the fermentation must or an aqueous solution reconstituted from the powder obtained according to the process described above, using one or more enzymes.
By way of enzymes which may be suitable for this purpose, mention may be made of proteases, mutanases, lipoproteases, cellulases and chitinases.
The enzymatic purification can be combined or replaced with physical purification processes, such as the various filtration, centrifugation or dialysis methods, or with various chromatographic techniques.
The fermentation musts and the reconstituted solutions of heteropolysaccharide (HP), possibly having undergone purification treatment, can be concentrated.
Concentration can be advantageous in certain cases, in particular when the transport costs can thus be decreased. In addition, the concentrated solutions can be more rapidly used than the heteropolysaccharide (HP) powders.
The concentration can be carried out by all the techniques known to those skilled in the art, in particular evaporation, ultrafiltration or diafiltration.
In the present invention, the heteropolyaccharide (HP) is advantageously present in the form a solid of fiber or powder type.
As already mentioned, (HP) has very good rheological properties, and in particular the ability to form true gels. Depending on the fermentation conditions, in particular depending on the components and the concentrations thereof in the culture medium, and/or the precipitation conditions in step (ii) of the process (more particularly whether or not the precipitation takes place in the presence of salts), (HP) has the advantage of being able to be used as a thickening agent or as a gelling agent, or both.
Thus the present invention relates to the use of the heteropolysaccharide (HP) as described above or as obtained by the process defined above, as a thickening and/or gelling agent.
(HP) can be used as a thickening and/or gelling agent, for example in the petroleum, agrochemical, food, cosmetics, paper and textile industries, and also in paints, contact lenses, glues, inks and household or industrial cleaners.
The amount of heteropolysaccharide (HP) of the invention which can be used in cosmetic compositions depends on the aqueous medium to be thickened and/or to be gelled. This amount can represent from 0.01% to 5% approximately, preferably about 0.1% to 0.3%, of the weight of the thickened or gelled aqueous medium.
The term xe2x80x9ccosmetic composition or formulationxe2x80x9d is intended to mean all the cosmetic products or preparations such as those described in annex 1 (xe2x80x9cIllustrative list by category of cosmetic productsxe2x80x9d) of European directive No. 76/768/EEC of Jul. 27, 1976, termed cosmetic directive.
The cosmetic compositions can be formulated into a large number of types of products for the skin and/or the hair, such as mousses, gels (in particular styling gels), conditioners, formulations for hair styling or for facilitating the combing of hair, rinsing formulations, hand and body lotions, products which regulate skin moisturization, cleansing milks, make-up-removing compositions, creams or lotions for protection against the sun and ultraviolet rays, care creams, anti-acne preparations, local analgesics, mascaras, products intended to be applied to the lips or other mucous membranes, sticks and other compositions of the same type.
These cosmetic compositions make use of a vehicle, or of a mixture of several vehicles, present in said compositions at concentrations of between 0.5% and 99.5% approximately, generally between 5 and 90% approximately.
The choice of the suitable vehicle depends on the nature of the ingredients used and on the destination of said compositions, depending on whether the formulated product is supposed to be left on the surface to which it has been applied (for example sprays, mousses, tonic lotion or gels) or, on the other hand, rinsed after use (for example, shampoo, conditioner, rinsing lotions).
The aqueous vehicles present in the cosmetic compositions can also contain C1-C6 alcohols, in particular methanol, ethanol and isopropanol. They can also contain another solvent making it possible to solubilize or disperse, in the aqueous medium, the various ingredients used in said compositions.
Said vehicles can thus also contain a large variety of other solvents, such as acetone, hydrocarbons, halohydrocarbons, linalool volatile silicones and esters. The various solvents which can be used in the aqueous vehicles may or may not be miscible with each other.
When the cosmetic compositions are in the form of sprays, tonic lotions, gels or mousses, the preferential vehicles comprise, besides water, ethanol, volatile derivatives of silicone, and mixtures thereof.
The formulations for aerosol sprays and mousses can also contain a propellant capable of generating the products in the form of mousse or fine sprays, which are uniform. By way of examples, mention may be made of trichlorofluoromethane, dichlorodifluoromethane, difluoroethane, dimethyl ether, propane, n-butane or isobutane.
Said aqueous vehicles can have a large number of forms, in particular those of emulsions, including the water-in-oil emulsions, oil-in-water emulsions, and multiple emulsions, the desired viscosity of which can range up to 2000000 mpaxc2x7s.
Besides the aqueous vehicle, the cosmetic compositions can contain surfactants, used to disperse, emulsify, solubilize and stabilize various compounds used in particular for their emollient or wetting properties. They can be of anionic, nonionic, cationic, zwitterionic or amphoteric type; by way of examples, mention may be made of:
anionic surfactants in an amount which can range from 3% to 50%, preferably from 5% to 20%, agents such as
alkyl ester sulfonates
alkyl sulfates
alkylamide sulfates
salts of saturated or unsaturated fatty acids nonionic surfactants in an amount which can range from 0.1% to 30%, preferably from 2% to 10%, agents such as
polyoxyalkylenated alkylphenols
glucosamides, glucamides
glycerolamides derived from N-alkylamines
polyoxyalkylenated C8-C22 aliphatic alcohols
the products resulting from the condensation of ethylene oxide with a hydrophobic compound resulting from the condensation of propylene oxide with propylene glycol,
amine oxides
alkylpolyglycosides and the polyoxyalkylenated derivatives thereof
amides of C8-C20 fatty acids
ethoxylated fatty acids
ethoxylated amidoamines, amines, amides
amphoteric and zwitterionic surfactants in an amount which can range from 0.1% to 30%, preferably from 1% to 10%, agents such as
those of betaine type such as
betaines
sulfobetaines
amidoalkylbetaines
and sulfobetaines
alkylsultaines
the products of condensation of fatty acids and of protein hydrolysates,
cocoamphoacetates and cocoamphodiacetates
alkylampho-propionates or -dipropionates,
amphoteric derivatives of alkylpolyamines
Conditioner s can also be present, in an amount which can range from 0.05% to 5%, preferably from 0.1% to 1%. Among these, mention may be made of those of synthetic origin which are better known under the name polyquaternium, such as the polyquaterniums xe2x88x922, xe2x88x927 and xe2x88x9210, the cationic derivatives of polysaccharides, such as hydroxyethyl cocodimonium cellulose, guar hydroxypropyl trimonium chloride, hydroxypropyl guar hydroxypropyl trimonium chloride, the nonvolatile derivatives of silicones, such as amodimethicone, cyclomethicones, non-water-soluble and nonvolatile organopolysiloxanes, such as-oils, resins or gums such as diphenyldimethicone gums.
The cosmetic compositions can also contain polymers with film-forming properties which can be used to provide an attaching function. These polymers are generally present at concentrations of between 0.01 and 10%, preferably of between 0.5 and 5%. They are preferably of the type polyvinylpyrrolidone, copolymers of polyvinylpyrrolidone and of methyl methacrylate, copolymers of polyvinylpyrrolidone and of vinyl acetate, polyethylene glycolterephthale/polyethylene glycol copolymers, and sulfonated terephthalic copolyester polymers.
The cosmetic compositions can also contain polymeric derivatives which exert a protective function, in amounts of about 0.01-10%, preferably approximately 0.1-5% by weight, derivatives such as
cellulose derivatives
polyvinyl esters grafted onto polyalkylene trunks
polyvinyl alcohols
sulfonated terephthalic copolyester polymers
ethoxylated monoamines or polyamines, polymers of ethoxylated amines
The performances of the cosmetic compositions can also be improved by using plasticizers in an amount which can range from 0.1 to 20% of the formulation, preferably from 1 to 15%. Among these agents, mention may be made of adipates, phthalates, isophthalates, azelates, stearates, silicon copolyols, glycols, castor oil, or the mixtures thereof.
It is also possible to advantageously add to these compositions metal-sequestering agents, more particularly those which sequester calcium, such as citrate ions, or polymeric dispersing agents in an amount of about 0.1-7% by weight, in order to control the calcium and magnesium hardness, agents such as
water-soluble salts of polycarboxylic acids
polyethylene glycols of molecular mass of about 1000 to 50000.
It is also possible to incorporate into the cosmetic compositions wetting agents; mention may be made of glycerol, sorbitol, urea, collagen, gelatin and emollients which are generally chosen from alkylmono-glycerides and alkyldiglycerides, triglycerides, such as oils extracted from plants and from vegetables or oils of animal origin or the hydrogenated derivatives thereof, mineral oils or liquid paraffins, diols, fatty esters and silicones.
To these compounds, it is possible to add, in combination, inorganic particles or powders such as calcium carbonate, inorganic oxides in the form of powder or in colloidal form such as titanium dioxide, silica, aluminum salts, kaolin, talc, clays and the derivatives thereof.
One or more fragrances, dyes and/or opacifyers such as pigments are generally added to these ingredients.
In order to protect the skin and/or hair against attacks from the sun and from UV rays, it is possible to add to these formulations sunscreens which are either chemical compounds which strongly absorb UV radiation, or inorganic particles such as zinc oxide, titanium dioxide or cerium oxides.
Preserving agents, such as p-hydroxybenzoic acid esters, sodium benzoate or any chemical agent which prevents bacterial proliferation or the proliferation of molds and which is conventionally used of the cosmetic compositions are generally introduced into these compositions to an amount of 0.01 to 3% by weight.
Agents which modify the activity of water and which greatly increase osmotic pressure, such as carbohydrates or salts, can sometimes be used.
The cosmetic composition can also contain other viscosity modifying and/or gelling polymers, such as crosslinked polyacrylates, hydrocolloids obtained by fermentation, such as xanthan gum and Rheozan, cellulose derivatives, such as hydroxypropylcellulose or carboxymethylcellulose, guars and the derivatives thereof, etc., used alone or in combination.
The invention relates more particularly to the use of the heteropolysaccharide as a thickening and/or gelling agent in dietary formulations.
The dietary formulations to which the heteropolysaccharide (HP) is added are conventionally simple or multiple liquid emulsions, complex gas and liquid emulsions (overrun systems), suspensions of liquids and solids, or any other system combining these possibilities.
In these formulations, the liquid is advantageously water or a liquid comprising water, at least in part.
The dietary formulations are obtained by implementing the conventional methods for preparing dietary formulations according to their type. Thus, the (HP) advantageously in the form of a solid of fiber or powder type is mixed with the other ingredients required for the formulation. The entire mixture can, where appropriate, be homogenized.
The temperature at which the formulation is prepared is not critical in itself. The formulations comprising the (HP) can be sterilized without any damage to their properties for use. Another advantage of (HP) is that it is possible to prepare the dietary formulations without having to heat the ingredients beforehand.
(HP) remains compatible despite the diversity of the dietary formulations (pH, ionic strength, composition), and substantially conserves its properties.
The advantageous theological properties associated with the heteropolysaccharide (HP) which is the subject of the invention, and also the ability of the latter to produce true gels at temperatures lower than or equal to 40xc2x0 C., this being within a wide pH range, also makes it possible to confer on the formulations in which it is used alone or in combination with other additives a texture close to that of the formulations comprising exclusively said additives.
The measurable parameters for characterizing the texture of the dietary formulations are rheological in nature, and consist essentially in measuring the elastic (Gxe2x80x2) and viscous (Gxe2x80x3) moduli, and the flow viscosity at a given shear rate. Gxe2x80x2 and Gxe2x80x3, and also the viscosity, have been defined above.
The objective of these rheological characteristics is to demonstrate the visco-elastic and/or pseudoplastic behaviors of the formulations, in order to compare them to each other.
(HP), advantageously in the form of a solid of fiber or powder type, has the ability to confer a rheofluidifying profile on the formulation comprising it.
(HP) has, similarly, the ability to produce true gels which can cicatrize after application of a mechanical stress.
It should be noted that the Gxe2x80x2 and Gxe2x80x3 moduli, and also the viscosity, measured for a formulation can be different from those measured for (HP) in distilled water.
In milk-based and set desserts, such as, for example, flans, it is possible to advantageously replace, at least partially, the usual gelling agents, in particular gelatin, with (HP).
In salty-acid media, such as vinaigrettes, the aqueous medium contained can be structured by adding small amounts of (HP).
In the field of confectionery, in particular in gum confectioneries of the HARIBO(copyright) type, it is possible to advantageously replace, at least partially, the gelling agents, such as for example gelatin, with (HP).
In media with high ionic strength, in particular in pork-butchery, (HP) can be added to the carrageenans in order to reinforce the texture, in particular the elastic appearance of sausages, for example.
In formulations intended to be overrun, such as Chantilly creams, toppings or ice creams, (HP) can be used as a thickening and/or gelling agent.
Similarly, (HP) can be used in formulations such as mayonnaises, vegetable mousses or mousses comprising proteins, for instance meat or fish mousses, or mousses comprising albumin, such as meringues.
As a thickening and/or gelling agent, (HP) can also be part of the composition of yoghurts.
In the abovementioned dietary applications, use is made in general of 0.01 to 5% by weight, and preferably between 0.05 and 2% by weight, of heteropolysaccharide (HP) with respect to the weight of the composition or formulation which contains it. Even more preferably, use is made of 0.1 to 1% by weight of heteropolysaccharide (HP) with respect to the weight of the composition or formulation.
It should be noted that the heteropolysaccharide (HP) does not modify the taste of the foods into which it is introduced.
The invention finally relates to the dietary compositions or formulations comprising the heteropolysaccharide (HP) as defined above.